Characterisation of cellulose-hydrolysing enzymes from the fungus Bipolaris sorokiniana

Cellulose-hydrolysing enzymes from the phytopathogenic fungus Bipolaris sor okiniana were partially purified and characterised. The enzyme production w as variable according to the carbon source. beta-Glucosidase and cellobiohy drolase activities were higher by growing the fungus on cellulose than on o ther carbon sources. Carboxymethyl cellulase production was stimulated by o ther carbohydrates, mainly lactose. Partial enzyme purification was carried out by Liquid chromatography on Sepharose CL4B. The purification was about 17-fold, with a yield of 41% as judged by assay with p-nitrophenyl-beta-D- glucopyranoside as substrate. The optimum pH and temperature were 5.0 and 5 5-60 degrees C respectively. The enzyme was stable at 28 and 37 degrees C b ut lost about 50% of its initial activity after 120 min at 55 degrees C. Sa ccharification of cellulosic materials such as crystalline cellulose, filte r paper and wheat straws was carried out using the partially purified enzym e, resulting in the production of reducing sugars. (C) 1999 Society of Chem ical Industry.